- make importorskip static at py.test.importorskip because it's

used for conditional plugin loading
- fix case where xfail is defined at module/class level
- fixes and improvements to docs, correct links to plugins
- use new skip facilities here and there

--HG--
branch : trunk

testing/code/test_assertion.py

@@ -135,11 +135,7 @@ def test_assert_with_brokenrepr_arg():
 class TestView:
 
     def setup_class(cls):
-        try:
-            from _py.code._assertionold import View
-        except ImportError:
-            py.test.skip("requires the compile package")
-        cls.View = View
+        cls.View = py.test.importorskip("_py.code._assertionold").View
 
     def test_class_dispatch(self):
         ### Use a custom class hierarchy with existing instances